This invention relates to bis-(2,5-polythio-1,3,4-thiadiazoles) and their use in the vulcanization of natural rubber, a rubber derived from a diene monomer and mixtures thereof.
In the manufacture of rubber articles, crude or raw rubber is compounded with various ingredients among which are sulfur and accelerators. The primary function of an accelerator or accelerator system is to increase the rate of the vulcanization process while allowing sufficient time to mix the accelerators into the rubber at an elevated temperature before vulcanization commences. Many accelerator combinations have been used in the rubber industry. Unfortunately, many of the known accelerators, such as morpholine containing compounds, dimethyl amine containing compounds and dithiocarbamate compounds yield volatile nitrosoamines upon use. The use of compounds which yield volatile nitrosoamines have been significantly restricted in a number of countries and the need to find a suitable replacement is imminent.